Aesop's Fables, translated by Laura Gibbs (2002)

A young man was walking along on a blazing hot day when he met an old
woman who was going the same way. Seeing that she was dreadfully exhausted
from the heat of the day and the demands of the journey, he felt sorry
for her weakness and when the woman simply didn't have the strength to
go any further, he picked her up off the ground and carried her on his
shoulders. While he was carrying her this way, the young man was so strongly
aroused by shameful thoughts that he had an erection. Spurred by wanton
lust and hot desire, he immediately put the old woman down on the ground
and had sex with her. Being simple-minded, the woman asked him, 'What
are you doing to me?' He answered, 'You are too heavy to carry, so I've
decided to carve off some of your flesh.' The man satisfied himself and
then picked the woman up off the ground again and set her on his shoulders.
After he had gone some way down the road, the old woman said to him, 'If
I am still too heavy a burden for you, you can put me down again and carve
off some more of me!' This fable shows that some people, when satisfying their own personal
desires, pretend as if the thing was done without their knowledge, giving
the impression that it is not actually a matter of desire, but rather
some practical necessity.

Source:
Aesop's Fables. A new translation by Laura
Gibbs.
Oxford University Press (World's Classics): Oxford, 2002.
NOTE: New
cover, with new ISBN, published in 2008; contents of book unchanged.